The existing ground fault circuit interrupter (GFCI) usually includes a pedestal, an upper cover with jacks, a leakage signal detection circuit, a mechanical tripping protection mechanism that is controlled by the leakage signal detection circuit, a contactor assembly, a grounding assembly, a power input connection assembly, a load connection assembly, etc. The GFCI can provide a load with a power supply not only through the socket holes on the upper cover but also through the load connection assembly. The leakage signal detection circuit has a leakage signal amplification integrated circuit as a core. A rectification bridge and an RC filter circuit provide the control circuit with DC power supply. The control output end of the leakage signal amplification integrated circuit is connected to the igniter of the tripping silicon control SCR1. The tripping silicon control SCR1 is connected in series in the power supply circuit of the tripping coil T3. The power supply wires L and N pass through a test toroidal coil T1 and a neutral toroidal coil T2. The output ends of the test toroidal coil T1 and the neutral toroidal coil T2 are connected to the leakage signal amplification integrated circuit.
Under normal conditions, the currents in the power supply wires L and N shall be equal. Once a leakage accident occurs, a difference is generated between the currents in the power supply wires L and N. The induction coil in the leakage protection device monitors the current difference and converts it into voltage signals, which are amplified by the leakage signal amplification integrated circuit and then outputted. Once the difference is more than a preset threshold value, the output control signal will cause the tripping mechanism to trip, cutting off the connection between the load power consuming equipment and the power supply wire so realizing the protection function.
However, the traditional GFCI does not have a protection function in the end of life period. That is to say, when any element in the GFCI is damaged, causing the life of the interrupter to come to an end, there is no appropriate reaction to warn the user that the GFCI has lost its neutral line leakage protection function and should be replaced. The traditional GFCI does not cut off the power supply in the load side forcibly. And, the user may believe mistakenly that it still functions. Once leakage occurs, there may be a risk of electric shock resulting in personal injury or property damage.